Thread-chain cutter for sewing machines



March 17, 1964 w. R. SPIVEY 3,125,052

THREAD-CHAIN CUTTER FOR SEWING MACHINES Filed Oct. 6, 1961 2 Sheets-Sheet 1 IN V EN TOR.

WARREN R. SPIVEY ATTORNEY March 17, 1964 w. R. SPIVEY 3,125,052

THREAD-CHAIN CUTTER FUR SEWING MACHINES Filed Oct. 6, 1961 2 Sheets-Sheet 2 HO V.

413 Has 58 INVENTOR.

WARREN R. SPIVEY ATTOR NEY United States Patent 3,125,052 THREAD-CHAIN CUTTER FOR SEWING MACHINES Warren R. Spivey, Marvell, Ark.

Filed Oct. 6, 1961, Ser. No. 143,386 9 Claims. (Cl. 112252) This invention relates in general to thread-chain severing devices for sewing machines and, more particularly, to a device for severing the connecting thread chain between pairs of socks or similar apparel-articles and fusing the severed portion into a non-raveling end.

In the manufacture of inexpensive children socks and like articles, the socks are successively emitted by a sewing machine and are connected by a thin continuous cord or chain of synthetic fiber. 'It has been the practice in the prior art to sever this cord by means of a scissors and quickly tie a knot or sew the severed end to the body of the sock in order to prevent unraveling thereof. This, of course, is a tedious and time consuming method that materially increases the cost of the article.

-It is, therefore, a primary object of the present invention to provide a method for separating or severing the continuous cord or so-called thread-chain connecting socks successively stitched or seamed on a sewing machine.

It is another object of the present invention to provide a device of the type stated which can be readily attached to, or assembled in operative relationship upon a sewing machine.

It is a further object of the present invention to pro-- which is economical in cost, in maintenance, and in operation.

It is an additional object of the present invention to provide a thread-chain severing device of the type stated which is substantially automatic in operation.

With the above and other objects in view, my invention resides in the novel features of form, construction, arrangement, and combination of parts presently described and pointed out in the claims.

In the accompanying drawings (two sheets):

FIG. 1 is a perspective view of a sock sewing machine with the thread-chain severing device forming part of the present invention incorporated therein;

FIG. 2 is a fragmentary sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a fragmentary sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a fragmentary sectional view taken along line 44 of FIG. 1; and

FIG. '5 is a diagrammatic view of the electrical circuitry forming part of the present invention.

Referring now in more detail and by reference characters to the drawings which illustrate a preferred embodiment of the present invention, A designates a sock seaming machine having an outer housing 1 consisting of a front wall 2 and a rear wall 3 that are connected by two spaced parallel end walls 4, 5, and a somewhat semi-circular top wall 6. The sewing machine A is mounted on a table top 7 forming part of a suitable supporting structure 8 which is provided with downwardly extending flange members 9 formed on the table top 7 and support le s 10. The sewing machine A and supporting structure 8 are conventional and, therefore, not illustrated nor described in detail.

Provided for use with the sewing machine A is a threadchain severing device B which is mounted on the end wall 4- and extends outwardly therefrom. The severing device B generally comprises spaced parallel side walls 11, 12, that are connected at their left transverse margins by an end wall 13 and together with the end wall 4 of the 3,125,052 Patented Mar. 17., 1964 ice 2 sewing machine A define a chamber 14. Disposed flatwise across the upper margins of the walls 11, 12, 13, and rigidly secured to the end wall 4 is a needle plate 15 which is provided with an aperture 16 communicating with the chamber 14. Rigidly secured to the end wall 4 within the chamber 14 and in downwardly spaced relation to the aperture 16 is an outwardly extending mounting block 17 upon which is mounted an upwardly extending support bracket 18 by means of screws 19. The support bracket 18 is integrally formed with a horizontal flange 2i} which is disposed lengthwise across the aperture 16. Seated securely in and extending upwardly from the flange 24 is a relatively coarse pitch guard-spiral 21 constructed of heavy-gauge wire so that the convolutions thereof are spaced apart. Mounted in and extending coax-ially through the spiral-guard 21 is a single strand of heater wire 22 which is preferably constructed of a high-resistance material. The heater wire 22 is structurally soldered and electrically connected at one end to the flange 2d and at its other end to a current conducting plate 23 which is mounted on the bracket 18 by means of dielectric insulators 2d. Mounted on the bracket 18 by means of a clamp 25 are a pair of electric conductors 26, 27, the conductor 26 being electrically connected at one end to the plate 23, and the conductor 27 terminating in an eyelet 28 which is then structurally attached and electrically grounded to the flange 18 by means of a screw 29. The other ends of the conductors 26, 27, suitably terminate in a plug Tall.

Mounted within the side wall 12 and communicating with the chamber 14 is a hollow tube 31 preferably formed 6f brass. The end of the tube 31 that terminates within the chamber 14 should also be polished to a smooth finish for preventing an accumulation of thread thereon. The tube 31 is also rigidly secured to the mounting block 17 by means of a clamp 32. Threadedly connected to the outer end of the tube 31 is a brass T-fitting t. A flexible rubber air line 33 is connected to one outlet of the T-fitting t and is connected at its other end to the inlet of a thread accumulation tank 34- which is, in turn, provided with a suitable exhaust fan 35. The tank 34 and exhaust fan 35 are conventional and, therefore, not described no rillustrated in detail.

Mounted on the undersurface of the table top 2 and abutting the inner surface of one of the downwardly extending flanges 9 is a control box 36 which generally comprises a rectangular sheet metal housing 37 and which includes a front wall 38, a rear wall 39, and a bottom wall 40, the front and rear walls 38, 39', being connected at their transverse ends by a left side wall 41 and a right side wall 42. The side walls 41, 42, terminate at their upper margins in laterally projecting flanges 43, 44, respectively by which the housing 3 7 may be secured to the underside of the table top 2. A power trans-former 45 having a primary winding 46 and a secondary winding 47 enclosed within a metal casing 48 which is provided with depending flanges 49 is secured to the right side Wall 42 by means of screws 5%. Suitably mounted in the front wall 38 in aligned relationship are a variable resistor 51, a toggle-switch 52 having an operating lever 53, a second spring-biased off toggle-switch 54 having an operative lever 55, a fuse receptacle 56 provided with a replaceable fuse 57, and a pilot light 53. Rigidly mounted on the rear Wall 39 by means of screws 59 are brackets 66 and secured thereto by means of screws 61 is a terminal board 62 constructed of formica or other suitable dielectric material. Suitably mounted in the left side wall 41 is a jack or plug receptacle 63 that is designed to accommodate the plug 30.

Also mounted within the rear wall 39 is a vacuum switch or so-called diaphragm switch 64 which includes a cylinder 65 and a pressure-responsive piston 66 having a piston rod 67. Extending coaxial to the piston rod 67 and mounted on the other side of the piston 66 is a sleeve 68 upon which is mounted a coil spring 69 that spring-biases the piston 66 inwardly. An outwardly extending pipe-fitting 70 is mounted on the cylinder 65 and communicates with the bore of the cylinder 65. A flexible rubber tube 71 is attached to the fitting 70 at one end and to the T-fitting t at its other end, thereby connecting the vacuum switch 64 to the air line 33. The vacuum switch 64 also includes a double-throw singlepole switch 72 mounted on one end of the piston rod 67 and having a contactor blade 73 that is movable between two contacts 74, 75.

As can be seen in FIG. 5, the terminals of the primary winding 46 are each connected to one wire of a twowire conductor or cord set 76. The fuse 57 and switch 52 are connected in series with the primary winding 46. The other end of the cord set 76 is provided with a conventional plug 77 so that the electrical thread-chain severing device may be connected to a suitable source of electrical power, and the primary winding 46 energized when the switch 52 is closed. The terminals of the secondary winding 47 are electrically connected at a common connection b on the terminal board 62. The secondary wind ing 47 is also provided with a center-tap e that is also grounded to the sheet metal housing 37. The pilot light 58 is connected across the common connection I; and the center-tap 2 so that the pilot light 58 will always be energized when a voltage is induced in the secondary winding 47 of the transformer 45. The variable resistor 51 is further connected to the common connection b of the two terminals and can be shunted from the circuit when the normally open toggle-switch 54 is closed. Finally connected in series with the variable resistor 51 is the vacuum switch 64 and a fixed resistor 78 which is electrically connected to the contact '75. The contactor blade 73 is normally biased to the contact 75 and the resistor 78 is shunted from the circuit when the contactor blade 73 is biased to the contact 74. Finally, one terminal of the jack 63 is connected in series with the fixed resistor 78, vacuum switch 64, and variable resistor 51. The other terminal of the jack 63 is grounded to the metal housing 37 to complete the circuit with the grounded center-tap e.

In use, the exhaust fan 35 is turned on in order to produce a continuous stream of air flowing through the aperture 16 into the chamber 14, and through the flexible air line 33 into the threaded accumulator tank 34. The plug 77 is connected to any common 110 volt receptacle and the switch 52 is closed, thereby energizing the primary winding 46 of the transformer 45. The resultant flux produced in the primary winding 46 will induce a voltage and current in the secondary coil 47 thereby lighting up the pilot light 58. As there is a continuous stream of fairly rapidly moving air in the hollow tube 31 and air line 33, the rubber tube 71 communieating with the hollow tube 31 will be under reduced pressure and the piston 66 will be urged outwardly against the action of the coil spring 69. The contactor blade 73 of the vacuum switch 64 is then biased to the contact 74, thereby shunting the resistor 78, from the circuit. The plug 30 is inserted into the jack 63 placing the heater wire 22 in series with the vacuum switch 64 and variable resistor 51. As the toggle-switch 54 is normally biased open, the voltage supplied to the heater wire 22 can be varied by means of the variable resistor 51. As the socks are successively emitted from the sewing machine A, they are passed over the aperture 16. The constant stream of air passing through the aperture 16 into the chamber 14 provides a positive force urging the con tinuous cord or thread-chain into the chamber 14 where it is brought into contact with the heater wire 22 through one of the convolutions in the guard 21. As the heater wire 22 severs the continuous cord from the sock, the excess material is carried by the stream of air through the air line 33 and into the thread accumulator tank 34. As the continuous cord is usually nylon or rayon the small portion of the cord remaining on the sock is welded into a non-raveling end. It is to be noted that the spiralguard 21 prevents the body of the sock or hands or clothing of the operator from coming into contact with the heater wire 22.

If desired, the normally open toggle switch 54 can be closed, thereby rendering a higher voltage in the heater; wire 22 in order to burn off any accumulation of yarn or knitted fabric that may have formed on the heater wire 22, while being operated at the normally lower temperature. The heater wire 22 is normally controlled by the large volume of air passing through the aperture 16. If, however, the exhaust fan 35 were turned off, stopping the large flow of air across the aperture 16, the heater wire 22 would rapidly burn out. To guard against such hazard, the contactor blade 73 of the vacuum switch 64 is biased to the contact point 75, placing the fixed resistor '78 in series with the variable resistor 51 and the heater wire 22. As long as there is an effective Vacuum in the system, the contactor 73 will occupy the position shown in full lines in FIG. 5, but if the vacuum goes olf, the contactor will automatically shift to the position shown in dotted lines, thereby reducing the current supplied to the heater wire 22. When the exhaust fan 35 is turned off, it will, of course require less current to maintain the heater wire 22 at operating temperature and the resistor 78 should be so designed as to pass this smaller amount of current when it is in the circuit.

It should be understood that changes and modifications in the form, construction, arrangement, and combination of the several parts of the electrical chain clipper can be made and substituted for those herein shown and described without departing from the nature or principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In combination with a sewing machine having a stitching means for stitching successive spaced sections of stitched material and feeding means for conveying the stitched material beneath and rearwardly from the stitching means, a said sewing machine further having means defining a substantially enclosed chamber extending beneath and rearwardly from the stitching means, said chamber having an aperture disposed rearwardly and in the path of the stitched material as it travels rearwardly from the feeding means, said aperture being relatively large with respect to the thread-chain so as to allow a substantial volume of air to flow through the aperture suction means communicating with said chamber for A drawing a substantial stream of air through said aperture, a heated wire mechanically supported beneath said aperture and interposed in the path of the air-stream so as to be cooled thereby when the aperture is unrestricted, means surrounding said heated wire for preventing stitched material from being sucked into direct contact with the heated wire while allowing a threadchain to be drawn across the heated wire for severance thereby, said aperture being so arranged that the air-flow therethrough will be intermittently restricted by the sections of stitched material as they pass over the aperture so as to reduce the cooling effect of the air-stream upon the heated wire and allow said wire intermittently to increase its temperature preparatory to each severing operation.

2. The combination as defined by claim 1 and in which the heated wire is heated by electricalsupply means whereby the thread-chain may be severed and the excess material carried away in the stream of air, vacuum switch means electrically interposed between said electrical supply means and said heated wire, said switch means being adapted to vary the voltage to said heated wire, and sensing means operatively associated with said vacuum switch means for operating said switch means responsive to the volume of air passing through the guard means.

3. The combination defined in claim 1 and further characterized by a control housing remotely located from said support means, electrical means within said housing for furnishing electric current to said high-resistance heating element, and conductor means connecting said electrical means to said heating element, whereby said threadchain may be severed and the excess material carried away in said stream of air.

4. The combination defined in claim 1 and further characterized by a control housing remotely located from said support means, electrical means within said housing for furnishing electric current to said high-resistance heating element, and conductor means connecting said electrical means to said heating element, said electrical means including a variable resistor for varying the voltage supplied to the heating element, whereby said threadchain may be severed and the excess material carried away in said stream of air.

5. The combination defined in claim 1 and further characterized by a control housing remotely located from said support means, transformer means mounted within said housing for furnishing electric current to said high resistance heating element, a variable resistor connected to said transformer means for varying the current supplied to said heating element, and conductor means electrically connecting the variable resistor to said heating element, whereby said thread-chain may be severed and the excess material carried away in said stream of air.

6. In combination with a sewing machine, a device for severing a thread-chain said device including a support means, a straight length of a high resistance heating wire carried by the support means, guard means encircling said heating wire having an opening defined by margins located outwardly from the wire said opening being sized to permit only small objects such as a thread-chain to be drawn into physical contact with the heated wire extending coaxially therewith, means for drawing a large volume of air through said guard means in a direction with respect to said thread-chain so as to bring the thread-chain into contact with said heating wire through said guard means, a control housing remotely located from said support means, transformer means mounted within said housing having a primary connected to a conductor adapted for connection to a source of electric current and a secondary adapted for furnishing electric current to said high resistance heating wire, a variable resistor connected in series with the secondary for varying the current supplied to said heating wire, switch means electrically connected in series between said variable resistor and said heating wire, and being adapted to reduce the electric current to the heating wire, and sensing means operatively associated with said switch means for operating said switch means responsive to substantial change in the volume of air blowing through the guard means so that when the air flow is substantially reduced the electric current to the heating wire is reduced whereby said thread-chain may be severed and the excess material carried away in said stream of air.

7. A device for severing a thread-chain as defined in claim 6 and further characterized by a fixed resistor interposed between said variable resistor and said heating element, whereby said thread-chain may be severed and the excess material carried away in said stream of air.

8. A device for severing a thread-chain as defined in claim 6 and further characterized by a fixed resistor interposed between said variable resistor and said heating element, and means interposed in the pathway of the large volume of air passing through the slotted guard means for shunting said fixed resistor from the circuit when air is passing through the slotted guard means, whereby said thread-chain may be severed and the excess material carried away in said stream of air.

9. The combination defined in claim 1, in which the means surrounding the heated wire is an open-convolution spring.

References Cited in the file of this patent UNITED STATES PATENTS 1,054,520 Eldridge Feb. 25, 1913 2,356,378 Capolupo Aug. 22, 1944 2,661,519 Rubin Dec. 8, 1953 2,867,184 Klapper Jan. 6, 1959 3,008,437 Herr Nov. 14, 1961 3,015,600 Cook Ian. 2, 1962 3,050,972 Billi Aug. 28, 1962 3,058,438 Russell et al. Oct. 16, 1962 FOREIGN PATENTS 311,048 Germany Feb. 21, 1919 228,116 Great Britain Oct. 15, 1925 

1. IN COMBINATION WITH A SEWING MACHINE HAVING A STITCHING MEANS FOR STITCHING SUCCESSIVE SPACED SECTIONS OF STITCHED MATERIAL AND FEEDING MEANS FOR CONVEYING THE STITCHED MATERIAL BENEATH AND REARWARDLY FROM THE STITCHING MEANS, A SAID SEWING MACHINE FURTHER HAVING MEANS DEFINING A SUBSTANTIALLY ENCLOSED CHAMBER EXTENDING BENEATH AND REARWARDLY FROM THE STITCHING MEANS, SAID CHAMBER HAVING AN APERTURE DISPOSED REARWARDLY AND IN THE PATH OF THE STITCHED MATERIAL AS IT TRAVELS REARWARDLY FROM THE FEEDING MEANS, SAID APERTURE BEING RELATIVELY LARGE WITH RESPECT TO THE THREAD-CHAIN SO AS TO ALLOW A SUBSTANTIAL VOLUME OF AIR TO FLOW THROUGH THE APERTURE SUCTION MEANS COMMUNICATING WITH SAID CHAMBER FOR DRAWING A SUBSTANTIAL STREAM OF AIR THROUGH SAID APERTURE, A HEATED WIRE MECHANICALLY SUPPORTED BENEATH SAID APERTURE AND INTERPOSED IN THE PATH OF THE AIR-STREAM SO AS TO BE COOLED THEREBY WHEN THE APERTURE IS UNRESTRICTED, MEANS SURROUNDING SAID HEATED WIRE FOR PREVENTING STITCHED MATERIAL FROM BEING SUCKED INTO DIRECT CONTACT WITH THE HEATED WIRE WHILE ALLOWING A THREADCHAIN TO BE DRAWN ACROSS THE HEATED WIRE FOR SEVERANCE 